Is 2 megapixels enough for 4x6 prints?

Question

My compact camera has a burst mode, which shoots 10 fps at 2 megapixels.

I plan to use it at an upcoming company sporting event (basketball and tennis, outdoors) and plan to post memorable moments at our company bulletin board and boardroom. That is, print the photos uncropped at 4x6 inches. I have a class 10 SD card.

Do I need (to shop for) a "better" camera?

Answer

As a rough rule of thumb, photos tend to be printed at a maximum of 300 dots per inch (dpi), but anywhere from around 240dpi will produce a print that looks sharp when viewed closely. 300dpi means that every 1" × 1" square of print is actually made up of a grid of tiny dots, 300 dots along each side (and therefore 90,000 dots in total).

A digital camera's sensor also captures a grid of dots. The dots are known as pixels and 1 megapixel = 1,000,000 pixels.

We now have all we need to do a simple bit of maths. :)

A 6x4" print at an optimum resolution of 300dpi will be made up of (6 × 300) × (4 × 300) = 2,160,000 dots: just a touch over 2 megapixels. However, to print at a perfectly acceptable 240dpi we only need (6 × 240) × (4 × 240) = 1,382,400 pixels.

Result: a 2mp camera should produce great 6×4" prints!

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